Module 2.3.2 (Management of DVT:PE) Flashcards
Define;
A) PE (Pulmonary embolism):
B) DVT (Deep vein thrombosis):
collectively known as venous thromboembolism
A)
- A pulmonary embolism (PE) occurs when a clot breaks loose and travels through the bloodstream to the lungs
B)
- Deep vein thrombosis (DVT) occurs when a blood clot (thrombus) forms in one or more of the deep veins in your body
> hip
> leg
> calf
What are the signs and symptoms of DVT? Where do the majority of thrombus form?
May be asymptomatic when present, symptoms may be non-specific
- Unilateral leg swelling or pitting oedema
- Pain, tenderness
- Erythema and warmth
- Pain on dorsiflexion
- Skin discoloration
- Dilated superficial veins
Majority of thrombus forms in the deep veins of the legs, thighs, or pelvis
Is the clinical diagnosis of DVT reliable or unreliable?
Relatively unreliable
For complications of DVT;
A) How often does recurrent DVT occur within 10 years?
B) What is post-thrombotic syndrome? What are the signs and symptoms associated with it?
C) How is PE related to DVT?
A)
- 30% within 10 years
B)
- Long term complication caused by damage to the venous valves
- Develop in 25-50% of patients
- S and S: chronic lower extremity swelling, pain, tenderness, skin discoloration, ulceration
C)
- Approx 70% of patients with PE have concomitant DVT
- Silent PE present in at least 1/3 patients with symptomatic DVT
What are the signs and symptoms of PE? Divide answer into common and less common.
highly variable and often non-specific, depends on the thromboembolic burden
Common:
- Shortness of breath –> sudden onset or evolving over days to weeks
- Palpitations (tachycardia)
- Dull central chest pain (may also be substernal or compressing)
Less common:
- Haemoptysis
- Syncope or dizziness (with massive PE)
- Pleural rub due to inflammation
- Fever (with co-existing infection and/or pulmonary infarction)
What is the 30-day mortality percentage of PE? What are long term complications associated with PE?
30-day mortality: 20%
- Long term complication: chronic thromboembolic pulmonary hypertension (0.1-4%)
What are the FOUR methods of diagnosing DVT and PE?
-
Clinical decision rules
* Wells score and Revised Geneva score –> estimation of the probability of a DVT/PE event - D-dimer testing
- <500ug/L (or age-adjusted in patients >50 years) to exclude VTE
- If < 500 ug/L –> no need for imaging
- Imaging for DVT
- Compression ultrasonography (whole-leg or two-point)
- CT or MRI or CT venography in some situations
- Imaging for PE
- CT pulmonary angiography
- Ventilation-perfusion lung scanning
> In renal impairment, contrast allergy, pregnancy, young women
What are the THREE risk factors for VTE? (Virchow’s triad)
- Endothelial/ vessel wall injury
- Altered blood flow/stasis
- Blood hypercoagulability
What are the two consequences to altered blood flow/stasis? Briefly explain what causes these consequences.
- Reduced mobility
- Paralysis, bed rest, immobilisation during surgery
- Long haul air travel (>4 hours = economy class syndrome)
- Occupation involving long periods of sitting
> e-thrombosis
- Sedentary lifestyle
2. Venous stasis (slow blood flow in the veins) - Tumors, obesity, pregnancy/post-partum period, varicose veins
- Class III/IV HF, MI, AF
For endothelial/vessel wall injury, what are FOUR potential causes?
- Major orthopaedic surgery
> Hip and knee replacement
- Trauma
> Vascular injury
> Fractures of hip, leg or pelvis
- In-dwelling venous catheters
- Previous DVT
For blood hyper-coagulability (increased tendency for blood to thrombose/clot);
A) What are some factors that cause it?
B) What are some medications that cause it?
C) What are examples of inherited coagulopathies (excessive clotting)?
D) What are examples of acquired coagulopathies?
A)
- Increasing age (>40)
- Obesity
- Smoking
- Family history of VTE
- Pregnancy/postpartum period
B)
- COC, HRT, tamoxifen, heparin (HITTS)
- Alcohol and hypnotics (sedation, dehydration)
C)
- Activated Protein C resistance (Factor V Leiden mutation)
- Protein C, Protein S deficincies
- Antithrombin (ATIII) deficiency
- Non-O blood group
D)
- Hyperhomocysteinaemia
- Antiphospholipid antibodies (SLE, IBD)
- Myeloproliferative disorders (polycythaemia) –> more RBC = predisposed to clotting
- Malignancy –> cancer strong factor for VTE
For prevention of VTE;
A) What are the basic rules
B) What is the range of situations of those who require VTE prophylaxis
C) What are the two modalities
A)
- Assess the need for VTE prophylaxis in all patients admitted to the hospital
- Discuss the patient’s preference
- Avoid dehydration; mobilise ASAP
- Continue VTE prophylaxis until the patient is no longer at increased risk
B)
- Non-surgical patients in hospital (e.g. HF, MI, active IBD)
- Surgical patients –> start at 6-12 hours post-op
- Lower limb immobilisation
- Thrombophilia, pregnancy, cancer
- Long-distance travel
C)
- Pharmacological and mechanical
For Pharmacological Prevention of VTE;
A) What are the 5 types of drugs used? Describe why they are used where appropriate?
B) What are the doses to answer A?
A)
- Low molecular weight heparins (LMWHs) –> dalteparin, enoxaparin, nadroparin
- Unfractionated heparin (UFG) –> preferred for patients with severe renal impairment or when rapid reversal of anticoagulation is necessary
- DOACs (apixaban, dabigatran, rivaroxaban) for VTE prophylaxis following hip or knee replacement
- Fondaparinux (Factor Xa inhibitor) –> alternative for patients undergoing major orthopedic surgery of lower limbs or abdominal surgery
- Danaproid/ (fondaparinux) for patients with known or suspected HIT (heparin-induced thrombocytopenia)
B)
see attached image
What drugs can be used for the following and how long to use it for;
A) Total hip replacement, hip fracture surgery
B) Total knee replacement
C) Major general surgery
A)
- LMWH or fondaprinux (or DOAC for total hip replacement) –> contiue for 28-35 days
B)
- LMWH or fondaparinux or DOAC –> continue for 10-14 days
C)
- LMWH or UFH –> continue for upto 1 week or until fully mobile
For Mechanical Prophylaxis;
A) Is it effective alone?
B) When is it preferred over pharmacological prophylaxis?
C) Which patients to avoid using in?
D) What are the methods? Provide THREE answers.
A)
- YES, it is effect alone
- Additive effect in combination with pharmacological prophylaxis
B)
- When risk of local bleeding is unacceptable (after neurosurgery, ophthalmic surgery
C)
- Avoid in patients at risk of ischaemic skin necrosis (e.g. severe peripheral arterial disease or peripheral neuropathy)
D)
- Graduated compression stockings providing 16-20 mmHg pressure at the ankle (antiembolism stockings)
> Must be profesionally fitted
> Surgical patients: fitted and worn preoperatively, continuing postoperatively until the patient is fully mobile
- Intermittent pneumatic compression devices
- Pneumatic foot compression or pump
